<?php

//  Set tracking option for the forum.

	require_once("../../config.php");
	require_once("lib.php");

	$id		 = required_param('id',PARAM_INT);						   // The forum to subscribe or unsubscribe to
	$returnpage = optional_param('returnpage', 'index.php', PARAM_FILE);	// Page to return to.

	if (! $forum = get_record("forum", "id", $id)) {
		error("Forum ID was incorrect");
	}

	if (! $course = get_record("course", "id", $forum->course)) {
		error("Forum doesn't belong to a course!");
	}

	if (! $cm = get_coursemodule_from_instance("forum", $forum->id, $course->id)) {
		error("Incorrect cm");
	}

	require_course_login($course, false, $cm);

	$returnto = forum_go_back_to($returnpage.'?id='.$course->id.'&f='.$forum->id);

	if (!forum_tp_can_track_forums($forum)) {
		redirect($returnto);
	}

	$info = new object();
	$info->name  = fullname($USER);
	$info->forum = format_string($forum->name);
	if (forum_tp_is_tracked($forum) ) {
		if (forum_tp_stop_tracking($forum->id)) {
			add_to_log($course->id, "forum", "stop tracking", "view.php?f=$forum->id", $forum->id, $cm->id);
			redirect($returnto, get_string("nownottracking", "forum", $info), 1);
		} else {
			error("Could not stop tracking that forum", $_SERVER["HTTP_REFERER"]);
		}

	} else { // subscribe
		if (forum_tp_start_tracking($forum->id)) {
			add_to_log($course->id, "forum", "start tracking", "view.php?f=$forum->id", $forum->id, $cm->id);
			redirect($returnto, get_string("nowtracking", "forum", $info), 1);
		} else {
			error("Could not start tracking that forum", $_SERVER["HTTP_REFERER"]);
		}
	}

?>
